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Finding the Fourth Proportional to 42.75, 64.09 and 18.38

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Solution

The fourth proportional to 42.75, 64.09 and 18.38 is: 27.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.75 : 64.09 = 18.38 : x
  2. Step 2: Convert to fraction form
    42.75/64.09 = 18.38/x
  3. Step 3: Cross multiply
    42.75x = 64.09 × 18.38
  4. Step 4: Simplify right side
    42.75x = 1,177.80
  5. Step 5: Solve for x
    x = 1,177.80/42.75
  6. Step 6: Final answer
    x = 27.55

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.